Deposition of Fuel Impurities Within Thermal Barrier Coatings in Gas Turbine Hot Gas Paths

2021 ◽  
pp. 1-46
Author(s):  
Christian Hollaender ◽  
Werner Stamm ◽  
Oliver Lüsebrink ◽  
Harald Harders ◽  
Lorenz Singheiser
Keyword(s):  
Gas Turbine ◽  
Diffusion Model ◽  
Thermal Barrier Coatings ◽  
Thermodynamic Equilibrium ◽  
Vapor Deposition ◽  
Gas Turbines ◽  
Recent Literature ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Hot Gas

Abstract For the reliable operation of modern gas turbines, Thermal Barrier Coatings (TBCs) need to withstand a wide range of ambient conditions resulting from impurities in inlet air or fuels. When analyzing deposition of detrimental hot gas constituents, previous efforts largely focus on the investigation of solid and molten deposit interaction with TBCs. Recent literature and observations in gas turbines indicate that not only liquids can penetrate porous TBCs, but the deposition from gas phase inside of pores and cracks is also an aspect of TBC degradation. To investigate this vapor deposition process, a diffusion model has been coupled with a thermodynamic equilibrium solver. The diffusion model calculates vapor transport of trace elements through pores and gaps in the TBC, where the thermodynamic equilibrium solver calculates local thermodynamic equilibria to predict whether deposition takes place. In this work the model is applied to discuss deposition properties of calcium. In recent literature calcium has – in some cases – been reported to deposit inside of TBCs as pure anhydrite (CaSO4). An actual anhydrite finding in the TBC of a stationary gas turbine blade was reproduced applying the introduced model. The vapor deposition is shown to occur within and on top of the TBC, depending on a number of factors, such as: pressure, temperatures, calcium to silicon ratio and calcium to sulfur ratio. The successful alignment of conditions in real engines with model results will allow to address the increasing demand for more fuel- and operational flexibility of current and future gas turbines.

Deposition of Fuel Impurities Within Thermal Barrier Coatings in Gas Turbine Hot Gas Paths

2020 ◽  
Author(s):  
Christian Holländer ◽  
Werner Stamm ◽  
Oliver Lüsebrink ◽  
Harald Harders ◽  
Lorenz Singheiser
Keyword(s):  
Gas Turbine ◽  
Diffusion Model ◽  
Thermal Barrier Coatings ◽  
Vapor Deposition ◽  
Gas Turbines ◽  
Recent Literature ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Hot Gas ◽  
Wide Range

Abstract For the reliable operation of modern gas turbines, Thermal Barrier Coatings (TBCs) need to withstand a wide range of ambient conditions resulting from impurities in inlet air or fuels. A novel deposition model has been developed that enables the prediction of deposition and transport of gaseous species originating from impurities in the gas turbine working media. The successful alignment of conditions in real engines with model results will allow to address the increasing demand for more fuel- and operational flexibility of current and future gas turbines. When analyzing deposition of detrimental hot gas constituents, previous efforts largely focus on the investigation of solid and molten deposit interaction with TBCs. Recent literature and observations in gas turbines indicate that not only liquids can penetrate porous TBCs, but the deposition from gas phase inside of pores and cracks is also an aspect of TBC degradation. To investigate this vapor deposition process, a diffusion model has been coupled with a thermodynamic equilibrium solver. The diffusion model calculates vapor transport of trace elements through pores and gaps in the TBC, where the thermodynamic equilibrium solver calculates local thermodynamic equilibria to predict whether deposition takes place. The model can calculate deposition rates within TBCs by taking into account the chemical composition of impurities in the hot gas as well as pressure, temperature profile in the TBC, and the TBC’s pore structure. Utilizing the model, a wide range of different fuel chemistries can be analyzed to draw conclusions regarding possible effects on TBC lifetime. In this work the model is applied to discuss deposition properties of calcium. In recent literature calcium has — in some cases — been reported to deposit inside of TBCs as pure anhydrite (CaSO4). An actual anhydrite finding in the TBC of a stationary gas turbine blade was reproduced applying the introduced model. The vapor deposition is shown to occur within and on top of the TBC, depending on a number of factors, such as: pressure, temperatures, calcium to silicon ratio and calcium to sulfur ratio.

scholarly journals Impact of Cooling with Thermal Barrier Coatings on Flow Passage in a Gas Turbine

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 85
Author(s):  
Yuanzhe Zhang ◽  
Pei Liu ◽  
Zheng Li
Keyword(s):  
Gas Turbine ◽  
Thermal Barrier Coatings ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Thermal Barrier ◽  
Power Sources ◽  
Barrier Coatings ◽  
Flow Passage ◽  
Blade Cooling ◽  
The Impact

Inlet temperature is vital to the thermal efficiency of gas turbines, which is becoming increasingly important in the context of structural changes in power supplies with more intermittent renewable power sources. Blade cooling is a key method for gas turbines to maintain high inlet temperatures whilst also meeting material temperature limits. However, the implementation of blade cooling within a gas turbine—for instance, thermal barrier coatings (TBCs)—might also change its heat transfer characteristics and lead to challenges in calculating its internal temperature and thermal efficiency. Existing studies have mainly focused on the materials and mechanisms of TBCs and the impact of TBCs on turbine blades. However, these analyses are insufficient for measuring the overall impact of TBCs on turbines. In this study, the impact of TBC thickness on the performance of gas turbines is analyzed. An improved mathematical model for turbine flow passage is proposed, considering the impact of cooling with TBCs. This model has the function of analyzing the impact of TBCs on turbine geometry. By changing the TBCs’ thickness from 0.0005 m to 0.0013 m, its effects on turbine flow passage are quantitatively analyzed using the proposed model. The variation rules of the cooling air ratio, turbine inlet mass flow rate, and turbine flow passage structure within the range of 0.0005 m to 0.0013 m of TBC thicknesses are given.

Development of Advanced TBC for 1650 °C Class Gas Turbine

2021 ◽  
Author(s):  
Yoshifumi Okajima ◽  
Taiji Torigoe ◽  
Masahiko Mega ◽  
Masamitsu Kuwabara ◽  
Naotoshi Okaya
Keyword(s):  
Gas Turbine ◽  
Thermal Barrier Coatings ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Operating Temperature ◽  
Critical Role ◽  
Thermal Barrier ◽  
Barrier Coatings

Abstract Increasing operating temperature plays a critical role in improving the thermal efficiency of gas turbines. This paper assesses the capability of advanced thermal barrier coatings being developed for use in 1700 °C class gas turbines. Parts sprayed with these coatings were evaluated and found to have excellent durability and long-term reliability.

scholarly journals Effects of Alloy Composition on the Performance of Yttria Stabilized Zirconia–Thermal Barrier Coatings

1999 ◽  
Author(s):  
Josh Kimmel ◽  
Zaher Mutasim ◽  
William Brentnall
Keyword(s):  
Gas Turbine ◽  
Thermal Barrier Coatings ◽  
Gas Turbines ◽  
Base Alloy ◽  
Critical Factor ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Turbine Component ◽  
Industrial Gas Turbines ◽  
Materials Used

Thermal barrier coatings (TBCs) provide an alloy surface temperature reduction when applied to turbine component surfaces. Thermal barrier coatings can be used as a tool for the designer to augment the power and/or enhance the efficiency of gas turbine engines. TBCs have been used successfully in the aerospace industry for many years, with only limited use for industrial gas turbine applications. Industrial gas turbines operate for substantially longer cycles and time between overhauls, and thus endurance becomes a critical factor. There are many factors that affect the life of a TBC including the composition and microstructure of the base alloy and bond coating. Alloys such as Mar-M 247, CMSX-4 and CMSX-10 are materials used for high temperature turbine environments, and usually require protective and/or thermal barrier coatings for increased performance. Elements such as hafnium, rhenium, and yttrium have shown considerable improvements in the strength of these alloys. However these elements may result in varying effects on the coatability and environmental performance of these alloys. This paper discusses the effects of these elements on the performance of thermal barrier coatings.

Preparation and Distribution Analysis of Thermal Barrier Coatings Deposited on Multiple Vanes by Plasma Spray-Physical Vapor Deposition Technology

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
J. Mao ◽  
M. Liu ◽  
C. G. Deng ◽  
C. M. Deng ◽  
K. S. Zhou ◽  
...  
Keyword(s):  
Thermal Barrier Coatings ◽  
Plasma Spray ◽  
Vapor Deposition ◽  
Gas Turbines ◽  
Physical Vapor Deposition ◽  
Ceramic Layer ◽  
Thermal Barrier ◽  
Distribution Analysis ◽  
Barrier Coatings ◽  
Bond Layer

The multicomponent NiCoCrAlTaY coating as bond layer as well as the zirconia stabilized by yttrium oxide (YSZ) coating as top ceramic layer was deposited on duplex vane surface by plasma spray-physical vapor deposition (PS-PVD) system. The thickness and microstructure of thermal barrier coatings (TBCs) under the influence of duplex vane geometry were presented in this article. It has been proven that the entire surface of duplex vane was covered by NiCoCrAlTaY and YSZ coatings. The position with thickest coating was found close to the leading edge and trailing edge of the vane. In those places, the coating was approximately 80–100% thicker than in the other areas on duplex vane. The obtained results indicate that it is possible to manufacture the TBCs including metallic bond layer and top ceramic layer by PS-PVD process on multiple vanes for gas turbines.

Effects of Alloy Composition on the Performance of Yttria Stabilized Zirconia—Thermal Barrier Coatings

2000 ◽  
Vol 122 (3) ◽  
pp. 393-400 ◽  
Author(s):  
Josh Kimmel ◽  
Zaher Mutasim ◽  
William Brentnall
Keyword(s):  
Gas Turbine ◽  
Thermal Barrier Coatings ◽  
Gas Turbines ◽  
Base Alloy ◽  
Critical Factor ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Turbine Component ◽  
Industrial Gas Turbines ◽  
Materials Used

Thermal barrier coatings (TBCs) provide an alloy surface temperature reduction when applied to turbine component surfaces. Thermal barrier coatings can be used as a tool for the designer to augment the power and/or enhance the efficiency of gas turbine engines. TBCs have been used successfully in the aerospace industry for many years, with only limited use for industrial gas turbine applications. Industrial gas turbines operate for substantially longer cycles and time between overhauls, and thus endurance becomes a critical factor. There are many factors that affect the life of a TBC including the composition and microstructure of the base alloy and bond coating. Alloys such as Mar-M 247, CMSX-4, and CMSX-10 are materials used for high temperature turbine environments, and usually require protective and/or thermal barrier coatings for increased performance. Elements such as hafnium, rhenium, and yttrium have shown considerable improvements in the strength of these alloys. However, these elements may result in varying effects on the coatability and environmental performance of these alloys. This paper discusses the effects of these elements on the performance of thermal barrier coatings. [S0742-4795(00)02603-X]

Development of Nondestructive Testing Method for Examining Thermal Resistance of Thermal Barrier Coatings on Gas Turbine Blades

2013 ◽  
Author(s):  
Takayuki Ozeki ◽  
Tomoharu Fujii ◽  
Eiji Sakai ◽  
Tetsuo Fukuchi ◽  
Norikazu Fuse
Keyword(s):  
Thermal Resistance ◽  
Surface Temperature ◽  
Gas Turbine ◽  
Thermal Barrier Coatings ◽  
Laser Heating ◽  
Turbine Blades ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Gas Turbine Blades ◽  
Hot Gas

In order to improve the efficiency of electric power generation with gas turbines, the turbine inlet gas temperature needs to be increased. Hence, it is necessary to apply thermal barrier coatings (TBCs) to various hot gas path components. Although TBCs protect the substrate of hot gas path components from high-temperature gas, their thermal resistance degrades over time because of erosion and sintering of the topcoat. When the thermal resistance of TBCs degrades, the surface temperature of the substrate becomes higher, and this temperature increase affects the durability of the hot gas path components. Therefore, to understand the performance of serviced TBCs, the thermal resistance of TBCs needs to be examined by the nondestructive testing (NDT) method. This method has already been reported for TBCs applied to a combustion liner. However, recently, TBCs have been applied to gas turbine blades that have complex three-dimensional shapes, and therefore, an NDT method for examining the thermal resistance of TBCs on blades was developed. This method is based on active thermography using carbon dioxide laser heating and surface temperature measurement of the topcoat by using an infrared camera. The thermal resistance of TBCs is calculated from the topcoat surface temperature when the laser beam heats the surface. In this study, the developed method was applied to a cylindrical TBC sample that simulated curvature on the suction side of a blade, and the results showed the appropriate laser heating condition for this method. Under the appropriate condition, this method could also examine the thermal resistance of TBCs present at 70% of the height of the blade. With these results, this method could determine the thermal resistance within an error range of 4%, as compared to destructive testing.

The Development of Ceramic-Based Thermocouples for Application in Gas Turbines

2001 ◽  
Author(s):  
D. M. Farrell ◽  
J. Parmar ◽  
B. J. Robbins
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Development Project ◽  
Thermal Barrier ◽  
Laboratory Studies ◽  
Barrier Coatings ◽  
Hot Gas ◽  
Elevated Pressures ◽  
Signal Output ◽  
Harsh Conditions

A research and development project has recently been carried out to develop ceramic thermocouple probes (CTPs) capable of measuring temperatures up to 2000°C and rugged enough to withstand extended service in high-temperature gas turbine environments. Existing metallic thermocouple technology cannot withstand such conditions for sustainable periods of time. Following initial laboratory studies, CTP trials were carried out in power generation boilers (Farrell and Higginbottom, 1995). Prototype CTPs were subsequently developed for evaluation in gas turbine (GT) combustors (at atmospheric and elevated pressures) and in a Spey engine (Patent, 1996). The CTPs performed well under the harsh conditions imposed, demonstrating their mechanical integrity and consistency/sustainability of signal output. Initial studies have also been carried out with a view to applying ‘thin-layer’ ceramic thermocouples directly onto thermal barrier coatings to give surface temperatures on stator or other hot gas surfaces, and are briefly mentioned. Rowan Technologies and TÜV Energy Services are currently looking for companies interested in exploiting this new ceramic thermocouple technology.

The Effects of Environmental Contaminants on Industrial Gas Turbine Thermal Barrier Coatings

1996 ◽  
Author(s):  
H. E. Eaton ◽  
N. S. Bornstein ◽  
J. T. DeMasi-Marcin
Keyword(s):  
Gas Turbine ◽  
Thermal Barrier Coatings ◽  
Gas Turbines ◽  
Chemical Properties ◽  
Turbine Engines ◽  
Thermal Barrier ◽  
Gas Turbine Engines ◽  
Silicon Iron ◽  
Barrier Coatings ◽  
Industrial Gas Turbine

Thermal barrier coatings, (TBCs) play a crucial role in the performance of advanced aircraft gas turbine engines that power the commercial and military fleets. The same technology is currently being applied to the industrial gas turbines. However the task is more challenging. The environment of the industrial gas turbine is far more demanding. Studies are in progress delineating the relationships between time, temperature and the sinterability of candidate ceramics for use in industrial gas turbine engines. Typical sintering aids include the oxides and alkali salts of silicon, iron, magnesium and calcium. Other experiments focus on the role of the alkali compounds as they affect the mechanical and chemical properties of candidate materials.

Development of Advanced Thermal Barrier Coatings for Severe Environments

1995 ◽  
Author(s):  
Warren A. Nelson ◽  
Robert M. Orenstein ◽  
Paul S. DiMascio ◽  
Curtis A. Johnson
Keyword(s):  
Gas Turbine ◽  
Thermal Barrier Coatings ◽  
Gas Turbines ◽  
Field Experience ◽  
Practical Knowledge ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Barrier Coatings ◽  
Design Engineers ◽  
Component Design

Air plasma sprayed yttria-stabilized zirconia thermal barrier coatings (TBCs) have been successfully used to extend life of superalloy components in utility gas turbines. GE Power Generation has over ten years of field experience with TBCs on combustor hardware, and over 20,000 hours of field experience with TBCs on turbine nozzles. Despite this promising experience, the full advantage of TBCs can be achieved only when the reliability of the coating approaches that of the superalloy component substrate. Recent work at GE has emphasized characterization of mechanical properties and physical attributes of TBCs to understand better the causes of delamination crack growth and coating spallation. In addition, unique tests to examine the TBC response under conditions simulating severe gas turbine service environments have been developed. Through evaluation of the results from comparative TBC ranking tests, pre-production application experience and field test results, gas turbine design engineers and materials process engineers are rapidly gaining the practical knowledge needed to integrate the TBC into the component design.

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